Process of making indigo, &amp;c.



' ful Improvements in Processes HANS BELAR'I, OF HUDDERSFIELD, ENGLAND.

PROCESS OF MAKING INDIGO, &c.

Specification of Letters Patent.

Patented Oct. 22, 1907.

Application filed September 13,1906. sent! No- 334,413

Toall whom it may concern:

Be it known that I, I'IANS BELART, a citizen of Switzerlan(l,resi(1ingat Huddersfield, in the county of York; Kingdom of Great Britain, haveinvented new and usefor the Manufacture of Indigo and other ProductsFormed by Condensation, of which the following is a specification. d

Through the German Patent No. 137 955, the use of sodium-amid in themanufacture of indigo became known. I have however discovered that byemploying potassium and sodium compounds of snilin, naphthylamin,diphenylamin, tolylamin, xylylamin, as con- (lensing agents results areobtained which practically gives theoretical yields. In this mannerindigo can be obtained by heating most of theintermediate products todayused in the manufacture of avith these condensingagents. i Example I. In500 psrtsofanilin add under most energetic agitation 36 parts of sodiumwhile heating; When.

the sodium has comploteiji! disappeared add gradually 150 partsabsolutely dry di-sodium salt of phenylglycinortho-carboxylic acid, andheat with neflunconde'nser.

synthetical indigo f fiisflng heating When the reaction is te: inatedthe excess of anilin is distilled in mono. Tho residue is dissolved inwater and the-indigo is isolated by the usual known methods.

, Example II. In 5,00 parts of anilin add gradually under agitation 59parts of finely powdered sodium-amid,

and heat while agitating, until all the ammonia is disengaged, and thesodimn-phenylamid is formed. Now

add 150 parts absolutely dryvdi'sodiumsalt of phenyl'glycin-orthocarboxylic acid gradually, andheat with.

reflux condenser. When the reaction is terminated; the

excess of anilin is'distilled in ruacuo. The residue is dissolved-inwater and the indigo is isolated by the usual known methods.

I clairn:

, The process of making indpxyl end its derivatives, conphenylglycln inTiresence ofnrylamins with aryl-sodium.

In testimony whereof I have signed my name to this specification in thepre'sence of two subscribing witnesses. HANS nnmn'r.

Witnesses Amman mssgnn'o'r; STAINLEY E, BnnMALL.

